The present invention relates to telecommunications apparatus, methods, systems and apparatus for transmitting data to and/or receiving data from mobile terminals in a wireless communications system. In particular, the invention relates to reporting of channel state information in wireless communications systems.
Channel state information may be of particular relevance to the effective operation of machine type communication (MTC) devices in cellular telecommunications networks having orthogonal frequency division multiplex (OFDM) based radio access technology (such as WiMAX and LTE).
One of the key issues to be considered in the development of radio technology is fading. Fading can affect radio propagation in many ways: a receiver may receive multipath signals (taps) which show the effects of attenuation, time delay and phase shift. In order to overcome fading, link adaptation techniques are widely used for wireless communication.
In order to use link adaptation, channel state information (such as the channel quality indicator (CQI) introduced in LTE) needs to be obtained for each UE. CQI is the feedback of a measure of downlink channel quality from mobile terminal (e.g. user equipment, UE) to base station (e.g. eNodeB).